docs: fix typo (#5330)

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<!-- This is an auto-generated comment: release notes by coderabbit.ai
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## Summary by CodeRabbit

- **Documentation**
- Updated the Chinese tutorial for Socket.IO to remove outdated
configuration comments.


<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Co-authored-by: fengmk2 <suqian.yf@antgroup.com>

site/docs/tutorials/socketio.zh-CN.md

@@ -116,7 +116,6 @@ location / {
     # http://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_bind
 ```
 
-# proxy_bind       $remote_addr transparent;
 ## 使用 `egg-socket.io`
 
 开启 [egg-socket.io] 的项目目录结构如下：